Methods Of Purification Of Organic Compounds

Concept: Simple distillation is used when boiling points differ sufficiently.

Step 1: Observation.
Chloroform (low bp) and aniline (high bp) → simple distillation works.

Concept: Layer test is used for halides.

Step 1: Observation.
Bromide gives characteristic colored layer.

Concept:
• IUPAC naming rules

Step 1: Longest chain
Propane backbone

Step 2: Substituents
Two methyl groups at C-2 and Br at C-1

Step 3: Name
1-Bromo-2,2-dimethylpropane Final Conclusion:
Option (C)

Concept:

Step 1: Molar mass of AgBr


Step 2: Mass of Br in 0.188 g AgBr


Step 3: Percentage
Final Conclusion:
Option (E)

Step 1: Understanding the Concept:
Simple distillation relies on heating a liquid to its boiling point. A liquid boils when its vapor pressure equals the external atmospheric pressure. However, some liquids decompose at temperatures below their normal boiling point.

Step 2: Key Formula or Approach:
The approach is factual recall of separation techniques. To boil such liquids without decomposing them, we must lower their boiling point. This is achieved by lowering the external pressure acting on the liquid surface.

Step 3: Detailed Explanation:
The technique used is Distillation under reduced pressure, also known as vacuum distillation.
By using a vacuum pump to reduce the pressure inside the distillation apparatus, the vapor pressure of the liquid will equal the external pressure at a much lower temperature. Consequently, the liquid boils and distills at a temperature significantly lower than its normal boiling point, thus avoiding thermal decomposition.
A classic example is the purification of glycerol, which decomposes at its normal boiling point ( ) but can be safely distilled without decomposition at a lower temperature under reduced pressure.

Step 4: Final Answer:
The technique is distillation under reduced pressure (vacuum distillation).